<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="shortcut icon" href="../image/logo1.png">
    <script src="../js/demo4.js"></script>
    <style>
        * {
            padding: 0;
            margin: 0;
            box-sizing: border-box;
        }

        #app {
            width: 300px;
        }

        li {
            list-style: none;
            background-color: #FF9966;
            border: 1px solid #ffffff;
            padding: 5px;
        }

        li a {
            font-size: 24px;
            text-decoration: none;
            color: black;
        }

        #app ul {
            display: none;
        }

        #app h1 {
            text-align: center;
        }

        #app h1:hover {
            cursor: pointer;
            background-color: aqua;

        }
    </style>

</head>

<body>
    <div id="app">
        <h1 onclick="showList()">前端课程</h1>
        <ul id="list">
            <li><a href="#">HTML</a></li>
            <li><a href="#">CSS</a></li>
            <li><a href="#">JAVASCRIPT</a></li>
            <li><a href="#">CSS</a></li>
        </ul>
    </div>
</body>

</html>